My wife and I are seriously considering purchasing a Bionx system for our xtracycle rig. It is getting increasingly difficult to haul our two growing kids and they're not old enough or big enough to help pedal a tandem/triple. Everything we have seen about the system seems pretty positive, but we find it difficult to plunk down the considerable cash for the system without ever having ridden it. The nearest dealer I could find (we're in Boston) is NYCEwheels in NYC. Is there anyone out there in the Greater Boston area who has one of these who would be willing to let us have a spin? Barring that, does anyone have any other suggestions as to how we could get a test ride, short of going to NYCEWheels?

Yeah, Stokemonkey is really nice. My wife and I were in Portland a few years ago and managed to get a test ride then. Todd and crew are really great and I think Stokemonkey is one of the better things since sliced bread. For our part though, it has a few key limitations. It needs a large enough frame to have sufficient clearance for the motor and it does take up cargo space on the xtra. We're trying to get through this as inexpensively as possible. Right now the frames we have are all too small for the Stokemonkey and we'd like to avoid the added cost of a new frame. Also, the Bionx we priced out at Nycewheels came in cheaper. A third consideration is distance. We're in Boston and NY adds up to fewer carbon miles for shipping than OR.

You mentioned other geared motors, but Stokemonkey and Bionx are the only two I know of that are commercially available to fit on an existing bike without some sort of custom kit. Are there others? I heard someone at MIT was working on one, but it didn't seem as advanced yet. I'm sure it'll be truly excellent when it hits prime time, but I don't know how long we can wait.

I have ridden both the SM and the BMC geared hub motor. Both of these will give you more torque than the bionx or other direct drive hubs in general.

The BMC will be just as easy to install on your bike as the bionx as it also comes in a kit. This will run you probably $900 + your choice of battery. Here is the build I put on my X last fall. http://endless-sphere.com/forums/vie...php?f=6&t=7003
The newer version 600 W is beefier than the one I put on, and I would go that way if I were to do it again.

Check out BMC, ezee, or bafang for geared hub motors.

You can also go with the myriad other direct drive motors as well, but you'll need to run more power through them to work with a cargo bike.